Tuesday, 13 December 2011

Predicting Magnetic Storms

I was musing a while back about the GPS system, and what would happen if it suddenly went missing.
This weeks New Scientist says:

Over the past two decades, several solar flares and magnetic storms of varying intensity have hit Earth. Solar flares are surges of X-rays, gamma rays and extreme ultraviolet radiation, and they can damage electric grids, fry satellite electronics and endanger astronauts in space. Even passengers and pilots on aircraft flying over the poles are at risk.A team at Montana State University in Bozeman are automating the process of studying the sun, and have developed computer programs using image-processing techniques to identify changing features on the sun's surface.

Accurate forecasts of the sun's activity could prove very useful, and not just for the GPS system. Any electrical or electronic equipment could be compromised.

At 2:45 AM on March 13 1989, electrical ground currents created by the magnetic storm found their way into the power grid of the Hydro-Quebec Power Authority. Giant capacitors tried to regulate these currents but failed within a few seconds as automatic protective systems took them off-line one by one. Suddenly, the entire 9,500 megawatt output from Hydro-Quebec's La Grande Hydroelectric Complex found itself without proper regulation. Power swings tripped the supply lines from the 2000 megawatt Churchill Falls generation complex, and 18 seconds later, the entire Quebec power grid collapsed.

The cosmonauts on the Mir station were subjected to daily doses of about twice the yearly dose on the ground, and during the solar storm at the end of 1989 they absorbed their full-year radiation dose limit in just a few hours.

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